Instead of affairs with work colleagues, office emails and messages are increasingly becoming the intrusive “third person” threatening workaholic Britons’ marriages, they say.

One major law firm said that technology billed as helping set people free from the office is now a factor in as much as a quarter of new divorce cases.

Official figures published earlier this month show that adultery as a cause of marital break-up has fallen to an all-time low, cited in just 14 per cent of divorces granted to wives in 2012.

More than half of wives filing for divorce now simply cite their husband’s “unreasonable behaviour”, a broader category which can include a range of failings. A similar trend can be seen in divorces granted to husbands.

According to Pannone Solicitors, now part of the law firm Slater & Gordon, pressure on marriages stemming from the workplace is now a factor in around half of separations it handles.

The firm, which deals with around 250 divorces a year, estimates that one in four cases now feature allegations that spouses are not fully contributing to domestic life because they are spending too much time answering work emails or dealing with work-related matters while at home or on holiday.

Vicki McLynn, a partner at the firm, said that in a growing number of cases the office email was taking the place of the “other woman”.

“The remote use of work technology has become so frequently cited in claims of unreasonable behaviour that it has almost become the third party in many divorces, in the same way that allegations about inappropriate relations with an office colleague might perhaps have featured in the past,” she said.

“Technology has developed at such a rapid rate that whereas taking work home might previously have meant occasionally reading or writing a report, now there can be easy and constant remote contact with the office late at night, at weekends and during holidays too.”

She added: “Technology is sold as creating a better work-life balance, enabling people to work from home, but in many cases now it is becoming the problem.

“When clients come in and you sit down and talk to them about what has gone wrong in the marriage, what is striking is the number of people now saying that their spouse is simply unable to turn off from work.

“They talk about them coming home and, instead of taking an interest in the family and what they have been doing, they are checking emails or taking messages.

“They say things like ‘even when we are on holiday he is always on his laptop’ or ‘she is on her BlackBerry’.

“People often say is adultery the symptom rather than the cause of marriages breaking down.

“And it could be the case that people are bringing work home because the marriage is already on the rocks.

“The kind of situation we hear about is people looking at emails at home late in the evening – sitting in front of the television but with the laptop open so that they aren’t even engaging in something as simple as watching programme together.

“I’ve heard no any occasions of people being on holiday and being on the laptop or constantly accepting calls from the office.”